OSE Immunotherapeutics Announces First Clinical Results for BI 770371, a Novel Anti-SIRPα Monoclonal Antibody

Regulatory News:

OSE Immunotherapeutics SA (ISIN: FR0012127173; Mnemo: OSE) today announced that first Phase 1 results for BI 770371, a novel anti-SIRPα monoclonal antibody evaluated in advanced solid tumors, have been presented, at the European Society for Medical Oncology conference, held in Madrid, Spain (October 20 – 24, 2023).

BI 770371 is an IgG1 mAb that recognizes both the V1 and V2 variants of SIRPα. In many cancer types, CD47 forms a potent ‘don’t eat me’ signaling complex with SIRPα that triggers a cascade of events that enables cancer cells to avoid detection by the innate immune system and inhibits the ability of macrophage cells to fight cancer. By blocking the interaction between SIRPα and cluster of differentiation 47 (CD47), SIRPα antagonism enhances innate immunity and restores the immune function of myeloid cells in the tumor microenvironment.

Nicolas Poirier, Chief Executive Officer of OSE Immunotherapeutics, commented:

“We congratulate our partner Boehringer Ingelheim for this important new achievement, performed in the frame of our global collaboration and license agreement, which demonstrates their commitment to selective SIRPα inhibitors targeting myeloid cells. We are very pleased to potentially make our selective SIRPα inhibitor technology available to more patients through this strategic collaboration. With the V1 and V2 alleles being similarly expressed across humans in western countries, and V2 being more prevalent in the Asian region, the additional BI 770371 program highlights a new step forward in our partnership with Boehringer Ingelheim aiming to provide this selective SIRPα innovation for the benefits of more patients.”

The BI 770371 development program will extend the therapeutic potential of selective SIRPα antagonists in various diseases or disorders, covering the most prevalent allelic variants* of SIRPα, V1 SIRPα and V2 SIRPα expressed on myeloid cells.

Boehringer Ingelheim is currently evaluating BI 770371 as monotherapy and in combination with ezabenlimab, a PD1 inhibitor (BI 754091), in an open-label, dose escalation/dose expansion Phase I clinical trial (NCT05327946) conducted in Canada, USA and Japan in patients with advanced solid tumours. The first clinical results of BI 770371 presented at ESMO 2023 conference (Madrid, Abstract #697P) showed that adverse events were manageable during the on-treatment period, Maximal Tolerated Dose (MTD) has not been reached. This clinical trial is ongoing. Boehringer Ingelheim is also evaluating BI 765063 (formerly OSE-172) in different combinations with patients with recurrent/metastatic head and neck squamous cell carcinoma (HNSCC) or hepatocellular carcinoma (HCC) in a Phase 1b trial conducted in the United States, Europe and Asia (NCT05249426).